CODEWITHSUNDEEP
c#asp.net.netcombobox
Rahul Krishnan R
Rahul Krishnan R

Reputation: 89

Object reference not set to an instance of an object. getting this error

I am working on an ASP .Net C# project and I am a beginner in web programming. I get the below error at runtime:

Object reference not set to an instance of an object.

Below is my code:

protected void Page_Load(object sender, EventArgs e)
{
    txtUsername.Focus();
    if (cmbThemes.SelectedItem.Text=="Red")
    {
        pnlSignin.Border.BorderColor = Color.Orange;
    }
}

cmbThemes is a ComboBox.

Thanks in advance.

Upvotes: 0

Views: 1944

Answers (5)

Cris
Cris

Reputation: 13341

Check for values of your variables,one of your variable txtUsername or cmbThemes is NULL

Upvotes: 1

user3040553
user3040553

Reputation: 1

You have to first check that your combobox must not be empty before check condition. You can do either:

protected void Page_Load(object sender, EventArgs e)
{
    txtUsername.Focus();
    if (cmbThemes.SelectedItem!=null)
    {
       if (cmbThemes.SelectedItem.Text=="Red")
       {
         //OtherOperations
       }
    }
 }

or

protected void Page_Load(object sender, EventArgs e)
{
   txtUsername.Focus();
   if (cmbThemes.SelectedIndex > -1)
   {
      if (cmbThemes.SelectedItem.Text=="Red")
      {
         //OtherOperations
      }
   }
}

Upvotes: 0

Ringo
Ringo

Reputation: 3965

Is your combobox have any item yet? please make sure it has at least one item before you try to set or get any it's properties.

Upvotes: 0

TommyHaugland
TommyHaugland

Reputation: 171

Either set the default selectedindex of the combobox to something other than -1 or always check it SelectedItem == null before checking the text.

Upvotes: 0

Ehsan
Ehsan

Reputation: 32661

change 

if (cmbThemes.SelectedItem.Text=="Red")

to 

if (cmbThemes.SelectedItem !=null &&cmbThemes.SelectedItem.Text=="Red")
{}

Upvotes: 7

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